A.O. Smith Copper Boiler DW-720

Ensure the circulating pump is properly sized for the application

Check water hardness, system pressure drop, and temperature rise across the boiler

Oil the three oil cups (2 on the motor, 1 on the pump) as instructed on the oil tube

Add 2 or 3 teaspoonfuls of No. 20 non-detergent motor oil in bearing oil cups

Add 10 or 12 drops of No. 20 non-detergent motor oil in motor oil cups

Is the lubrication process completed for all oil cups?

Ensure the boiler is turned off and cooled down

Verify that all necessary tools and cleaning solutions are available

Check for contaminants in the system

Add the recommended percentage of cleaning solution to the system

Fire and circulate the system for about one hour

Flush the system with fresh water until clean

Ensure water softening equipment is operational

Check for lime build-up in the inlet/outlet manifold through the pressure relief valve tapping

Has there been a 5°F change in the normal temperature rise through the boiler?

Obtain UN•LIME from dealer or distributor

Read the instructions on the label of the UN•LIME container

Ensure all necessary equipment is made of copper or brass

Follow the typical piping arrangement for gravity deliming as shown in Figure 29

Remove cover panel from far side of water connections

Expose the heat exchanger return bends

Remove return bends using a 9/16" deep socket ratchet

Inspect tubes to ensure they are free of scale and deposits

Remove deposits with a stiff wire brush or mechanical tube cleaner to bare metal

Main Burner Flame Characteristics Check

Check for complete combustion of gas

Ensure rapid ignition and carryover of flame across entire burner

Verify reasonably quiet operation during initial ignition, operation, and extinction

Check for no excessive lifting of flame from burner ports

Is there any accumulation of lint or foreign material restricting air openings?

Clear any lint or foreign material from air openings if present